This is, by far, the best introduction to the textual criticism of the Hebrew Bible available. McCarter's presentation is clear, balanced, and well illustrated by the text-critical work he himself has done on the difficult text of Samuel and elsewhere.
Chapter 3, "The Basic Procedures of Textual Criticism," is especially helpful for those who are new to textual criticism. In this chapter McCarter provides a step-by-step procedure for identifying and evaluating textual difficulties. McCarter's procedures are both clear and concise, making this chapter a useful and extremely practical guide for performing textual-criticism on one's own.
McCarter includes three appendices at the end of this book. The first is a glossary of terms used in textual criticism. The second is a very useful (though now out of date) bibliography for primary sources used in textual criticism. The third, and most interesting, describes the characteristics of the various textual witnesses to each book of the Hebrew Bible. This appendix supplements McCarter's important comments in the body of his work about the importance of being familiar with the tendencies of each textual witness while evaluating textual difficulties.
This book is only 94 pages, including the appendices, but it is clearer and contains more information than books twice its size. After finishing this book readers should move on to Emmanuel Tov's, "Textual Criticism of the Hebrew Bible" (Second Revised Edition), which is more detailed in certain areas (though the detail is not always necessary) and is a little more up-to-date, but should keep this book close at hand because of its superior practicality.